Apparatus for spraying particulate material

ABSTRACT

Particulate material spraying apparatus comprises an extractor device having an inlet passage extending from the mouth of an inlet nozzle at one end of the inlet passage and a compressed gas passage extending past the other end of the passage to entrain particulate material through the inlet nozzle and inlet passage, to a flexible pipe leading to a spray gun. To prevent choking by accumulation of the material in or on the extractor device, the inlet nozzle has a tapered outer surface converging with the inlet passage at the mouth, and a vibrator is provided for vibrating the nozzle. The extractor device may be attached to the wall of a container for the particulate material, or may be separate from the container to facilitate transference of the extractor device to a different container.

O United States Patent 1 1 1111 3,896,998 Vertue July 29, 1975 [541APPARATUS FOR SPRAYING 2,545,829 3 1951 Spreng 222 193 I M TE AL3,134,513 5/1964 Ashman 222/193 PART CULATE A R 3,637,135 1/1972 Ludereret a1. 222/193 X Inventor: Charles t C le, 3,740,612 6/1973 Gauthier eta1. 117/934 x Canada 3,795,348 3/1974 Vertue 222/193 [73] Assignee:Volstatic of Canada Limited, FOREIGN PATENTS OR APPLICATIONS Canada651,407 4/1951 United Kingdom 222/193 [22] Filed: Feb. 1, 1974 PrimaryExaminer-Robert S. Ward, Jr. [211 PP 438,617 Attorney, Agent, orFirmStaas & Halsey Related U.S. Application Data [63]Continuation-impart of Ser. No. 314,737, Dec. 13, [57] ABSTRACT 1972,abandoned. Particulate material spraying apparatus comprises anextractor device having an inlet passage extending [30] ForeignApplication Priority Data from the mouth of an inlet nozzle at one endof the Sept. 25, 1972 Canada 152412 inlet P g and a compressed gasPassage extending Dec. 18, 1973 Canada 188393 P the other 9nd of thePassage to ehtraih Particulate material through the inlet nozzle andinlet passage, to 52 U.S. c1. 239/106; 239/318; 222/193; a flexible p pleading to a p y To Prevent 2 9 5; 3 5 239 54 choking by accumulation ofthe material in or on the [51] 305 5 02; 5053 5 02; 3 5 53/42 extractordevice, the inlet nozzle has a tapered outer [58] Field of Search 239/3,15, 8, 654, 106, surface converging with the inlet Passage at the239/310, 318, 340, 372; 1l7/93.4 R, 93.4 A, 93.4 NC, 17; 118/302, 7;317/3; 222/193; 302/58 [56] References Cited UNITED STATES PATENTS2,187,376 1/1940 Guibert 222/193 mouth, and a vibrator is provided forvibrating the nozzle. The extractor device maybe attached to the wall ofa container for the particulate material, or may be separate from thecontainer to facilitate transference of the extractor device to adifferent container.

15 Claims, 10 Drawing Figures PATENTEDJULZQIHIS 3,896,998

SHEET 2 FIG. 2.

PATENTEDJULZSISYS 3, 896,998

SHEET PATENTED Z IHYS a. 896,998

SHEET 4 PATENTED JUL 2 9 I975 SHEET FIG. 7.

APPARATUS FOR SPRAYING PARTICULATE MATERIAL lier application Ser. No.314,737, filed Dec. 13, 1972,

now abandoned.

The present invention relates to apparatus for spraying particulatematerials.

The spraying of materials in powdered form, such as synthetic resins andpigments, and powdered metals, onto substrate to form coatings on thesubstrates has the advantage that at least part of the material sprayed,but which does not form part of the coating, may be recycled for reuse,thus providing considerable economy and reduction of pollution incomparison to the use of liquid spraying.

For delivering particulate material to a spray gun, it has previouslybeen proposed to use an extractor device for extracting particulatematerial from a bed of the material, the extractor device having aninlet passage communicating at one end thereof with the bed through aninlet to the extractor device, and means for discharging compressed gas,e.g. air, past the other end of the inlet passage, so that particulatematerial is thereby entrained from the inlet passage through a flexiblehose to a spray gun.

It has been found that in practice the particulate material has atendency to deposit on and around the inlet to the extractor device andthereby build up into an accumulation of the particulate material whicheventually interferes with the flow through the inlet passage, causingthis flow to be choked and thereby causing an uneven discharge of theparticulate material from the spray gun. This effect may also be causedor increased by partial or complete blockage of the inlet passage byflakes or lumps formed by mutual adherence of recycled particles of theparticulate material.

In my co-pending patent application Ser. No. 278,320, filed Aug. 7, 1972now U.S. Pat. No. 3,795,348, issued Mar. 5, 1974, In have disclosed adevice for conveying particulate material by entraining the latter in aflow of gas, the device being provided with an inlet nozzle which, tocounteract accumulation of the particulate material, has an outersurface which tapers towards the mouth and converges with a passagethrough the nozzle, so that no shoulder is formed around the nozzlemouth which would facilitate such accumulation.

It is, accordingly, an object of the present invention to provideparticulate material spraying apparatus having novel and improved meansfor counteracting blockage of the flow of the particulate materialthrough the apparatus.

According to the present invention, a vibrator is provided for vibratingthe nozzle and further counteracts the deposition of particulatematerial on the unit and facilitates breaking-up of any lumps or flakesof the particulate material.

Further objects, features and advantages of the present invention willbe more readily understood from the following description thereof givenby way of example with reference to the accompanying drawings, wherein:

FIG. 1 shows a diagrammatic front view in elevation of a particulatematerial spraying apparatus according to the present invention;

FIG. 2 shows a view taken in vertical section through a powder funneland container forming part of the apparatus of FIG. 1;

FIG. 3 is a broken-away view illustrating part of the apparatus of FIG.1;

FIG. 4 shows a broken-away view taken in section along the line IV--IVof FIG. 3;

FIG. 5 shows a view taken in section through an outlet unit forming partof the apparatus of FIG. 1;

FIG. 6 shows a diagrammatic side view in transverse cross-section ofpowder conveying apparatus embodying the invention;

FIG. 7 shows a plan view of a housing and a powder extraction deviceforming parts of the apparatus of FIG. 6;

FIG. 8 shows a view taken in section along the line VIII-VIII of FIG. 7;

FIG. 9 shows a rear view of the housing and powder extraction device,viewed in the direction of arrow A of FIG. 7; and

FIG. 10 shows a view taken in cross-section through a powder inletnozzle and associated parts of the powder extraction device of FIGS. 6to 9.

With reference firstly to FIG. 1, the spraying apparatus illustratedtherein has a powder storage unit indicated generally by referencenumeral 10. The powder storage unit 10 has an upper frusto-conicalportion 11 disposed on a lower, cylindrical container portion 12.

As can be seen from FIG. 2, the lower, cylindrical container portion 12also supports a cylindrical powder retaining wall 14, which extendsupwardly from the lower cylindrical container portion 12 within thefrusto-conical portion 11. The cylindrical powder retaining wall 14 isprovided with a plurality of support struts 15, by which a conical cover16 is supported at a spacing above the top of the cylindrical powderretaining wall 14, the cover 16 projecting laterally beyond thecylindrical powder retaining wall 14.

The lower end of the cylindrical powder retaining wall 14 is providedwith a plurality of circumferentially spaced circular openings 17. Thefrusto-conical portion 11 contains a body of powder 18, which can flowthrough the openings 17 and drop into the underlying lower cylindricalcontainer portion 12.

The lowermost end of the lower cylindrical container portion 12 isclosed by a circular bottom 20. A membrane 21 extending transverselyacross the whole area of the interior of the lower cylindrical containerportion 12, and supported from the inner surface of the lowercylindrical container portion 12 by means of an annular support bracket22, divides the interior of the lower cylindrical container portion 12into an upper chamber 24 and a lower chamber 25.

The lower chamber 25 is provided with an inlet pipe 26 which isconnected by a branch 27 of the pipeline 28 (see FIG. 1) to a compressedair pump P.

The pump P is further connected by the pipeline 28, through branches 29and 30, to a pair of powder extractor devices 31, which in turn areconnected by flexible pipelines 32 to respective spray guns 33. Thespray guns 33 may for example by mounted on a reciprocating mechanism(not shown) for spraying articles in a spray booth (not shown), and maybe a conventional type of spray gun used for electrostatic coating.

Referring now to FIGS. 3 and 4, it will be seen that each of the twoextractor devices 31 are connected to a plate 35, on which there issupported a vibrator 36.

The plate 35 has an arcuately shaped portion 37, the curvature of whichcorresponds to that of the lower cylindrical container portion 12. Asheet 39 of rubber is sandwiched between the plate portion 37 and asimilarily arcuately curved metal plate 40. The rubber sheet 39 forms aclosure for an opening 42 formed in the wall of the lower cylindricalcontainer portion 12, and the plate 40 fits into, and is spaced from theedge of, the opening 42. The plate 35, with the vibrator 36 and theextractor devices 31, are thus resiliently supported by the rubber sheet39 on the lower cylindrical container portion 12.

Each of the extractor devices 31 has an inlet nozzle 60 projecting intothe interior of the lower cylindrical container portion 12 within thechamber 24.

FIG. shows in greater detail the construction of one of the extractordevices 31. As can be seen from FIG. 5, the unit illustrated therein hasa generally T-shaped body in the form of a Tee-piece indicated generallyby reference numeral 45, which is threaded at the ends of each of itsarms. Internally threaded retainers 46, 47 and 48 are in threadedengagement with these threaded arm ends of the Tee-piece 45. Theretainer 46 connects a flanged end of an outlet pipe 50 to the Tee-piece45, and the other end of the outlet pipe 50 is formed on its outerperiphery with annular ribs 52 for engagement with the respectiveflexible pipeline 32.

The retainer 47 engages a flange 54 on a nozzle 55 extending into theTee-piece 45 and thereby retains the nozzle member 55 in position asshown. The nozzle 55 has a threaded end 56 projecting away from theTeepiece 45 beyond the retainer 47 for engagement with the respectivebranch pipeline 29 or 30, this threaded end 56 being formed internallywith a flared mouth 57 communication with a bore 58, which in turnextends to and communicates with a discharge orifice 59 at the oppositeend of the nozzle 55.

The retainer 48 connects an inlet nozzle 60 to the third arm of theTee-piece 45 and clamps the Tee-piece 45 to the plates 35 and 40 and therubber sheet 39, the inlet nozzle 60 being formed with an annularshoulder 61 for engagement with the retainer 48. An inlet passage orbore 62 extending longitudinally through the inlet nozzle 60communicates with a bore 63 extending through one arm of the Tee-piece45 to a frustoconically diverging gas discharge passage 64, whichextends from the bore 63 to a cylindrical passage 65 extending throughthe interior of the pipe 50, the passages 64 and 65 being held inalignment by the retainer 46. The upper end of the bore 63 and thefrustoconically diverging gas discharge passage 64 form parts of aventuri, the nozzle discharge orifice 59 being directed towards thefrusto-conically diverging gas discharge passage 64 and communicatingwith the upper end of the bore 63.

The inlet nozzle 60 has a frusto-conically shaped outer surface 70,which tapers to the inlet end of the bore 62 to form a thin, annular,substantially knifeedged rim or mouth around the inlet end of the bore62,, where the outer surface 70 converges with the bore 62.

The operation of the above-described apparatus is as follows:

The powder 18, which for example may be a powder paint comprising amixture of powdered synthetic resin material and pigment particles, isdischarged through the open top of the frusto-conical portion 11 of thepowder storage unit or container 10, and deflected laterally by thecover 16 so that it accumulates between the wall of the frusto-conicalportion 11 and the cylindrical powder retaining wall 14. Some of thepowder 18 falls through the openings 17 into the lower cylindricalcontainer portion 12, and more particularly into the chamber 24.

A suitable gas under pressure, for example compressed air or an inertgas, is supplied by the pump P through the pipeline 28, the branchpipeline 27 and the inlet 26 into the chamber 25 and diffuses throughthe membrane 21 into the chamber 24, so that the powder in the chamberis fluidized.

The compressed air or inert gas is also supplied through the pipeline 28and the branch pipelines 29, 30 to each of the extractor devices 31, andmore particularly to the nozzles 55. In each extractor device 31 the,

air or gas flows through the orifice 59 into the frustoconical passageportion 64 and thereby entrains a mixture of gas and the powder 18 fromthe chamber 24 through the nozzle 60 and the inlet passage formed bybores 62 and 63 into the frusto-conically diverging passage portion 64,and thence through the cylindrical passage 65 of the pipe 50, andthrough the respective flexible pipeline 32, to one of the spray guns33, where the mixture is discharged onto a substrate which is to becoated.

At the same time, the vibrator 36 is energized to oscillate the plate35, which is resiliently supported by the rubber sheet 39, and therebyto vibrate the extractor devices 31 to prevent accumulation of powder atthe extractor devices 31 and in particular at the mouths of the inletnozzles 60. The accumulation of powder at the inlet end of each inletnozzle 60 is also counteracted by the tapering of the outer surfacethereof to the inlet end of the passage 62, so that no flat inlet end ispresented by the nozzle 60 on which powder could be accumulated.

A further problem which may arise when spraying powder paint may be arequirement that the spraying apparatus should be readily and quicklychanged over from powder of one colour to powder of a different col our.However, rapid changeover of the powder colour may be hindered by thefact that the powder tends to adhere to some extent to the apparatusemployed, and the adhering powder may contaminate powder of a differentcolour sprayed by the apparatus after the changeover.

Rapid changeover from powder paint of one colour to that of anothercolour is facilitated by the apparatus illustrated in FIGS. 6 through10.

The apparatus illustrated in FIG. 6 has a powder container indicatedgenerally by reference numeral 110, which is open-topped and which hasan upper, frustoconical portion 111 extending from a lower, cylindricalportion 112. A supply of paint powder 114 is held in the container on ahorizontal partition 115.

The horizontal partition 115 is made of a porous material, for exampleporous polyvinyl chloride, and provides a porous support surface for thepowder 1 14. The partition 115, together with part of the wall of thecylindrical container portion 112 and a bottom 116 closing the undersideof the container 110, form a compressed gas chamber 118, which has acompressed gas inlet opening 119.

On the upper, porous surface of the partition 115 there are supported ahousing indicated generally by reference numeral 120 and a powderextractor device indicated generally by reference numeral 121. Aflexible pipe 122 extends from the housing 120, and flexible pipes 123and 124 extend from the powder extractor device 121. The flexible pipes122, 123 and 124 extend upwardly to the open top of the container 111and are connected beyond the container to other apparatus which will bereferred to hereinafter.

As shown in FIGS. 7 to 9, the housing 120 is formed by an open-toppedmetal box 126 having at its top an inturned flange 127, and a porouswall portion in the form of a porous plate 128, which is secured to thetop of the box 126 in an airtight manner by means of a plurality ofrivets 129 extending through the flange 127.

A vibrator 130, which is operated by compressed air, is resilientlysupported within the housing 120 in a manner described in more detailhereinafter, and has an inlet 131 and an outlet 132 (FIG. 7) for theflow of the compressed air to and from the vibrator 130. The vibratoroutlet 132 discharges the compressed air directly within the interior ofthe container 120 and this compressed air then passes through the porousplate 128.

The vibrator 130 is connected, at the vibrator inlet 131, to aconnecting pipe 134, which extends to the exterior of the housing 120for connection to the flexible pipe 122, which serves to supply thecompressed air from a suitable soure, e.g. the pump P of FIG. 1, to thevibrator 130 for operating the latter.

The powder extraction device 121 is mounted on the connecting pipe 134by means of a support bracket indicated generally by reference numeral135, which is made of sheet metal and has a vertical portion 136, whichis clamped at its lower end around the connecting pipe 134 by means of asleeve 137 and a threaded collar 138 in threaded engagement with theconnecting pipe 134.

The upper end of the bracket is bent to provide a horizontal portion 140and two further vertical bracket portions 141 (see FIG. 7) extendingupwardly from the horizontal portion 140 and parallel to one another.

Each of the vertical bracket portions 141 supports two blocks 143 ofplastic material, which are secured thereto by means of nuts 144 andbolts 145 extending through the blocks 143. Each of the blocks 143 has apowder inlet nozzle 147, a compressed air inlet nozzle 48, and an outletnozzle 149 for the flow of a mixture of compressed air and entrainedpowder. The compressed air inlet nozzle 148 is connected to the flexiblepipe 124 (FIG. 6), which in turn is connected to a source of compressedair, e.g. the pump P of FIG. 1, and the outlet nozzle 149 is connectedto the flexible pipe 123. When the present apparatus is employed as partof a spraying apparatus, the flexible pipe 123 is connected to a spraygun, e.g. one of the spray guns 33 of FIG. 1. However, it is to beunderstood that the apparatus illustrated in FIGS. 7 to 9 may beemployed, for example, for transferring powder from one container toanother or for transferring powder from a supply box to the container110 or another container.

In addition, while only one of each of the flexible pipes 123 and 124have been illustrated in FIG. 1, for convenience of illustration, it isto be understood that each of the inlet nozzles 148 and each of theoutlet nozzles 149 is connected to a respective flexible pipe. Ofcourse, in a modification of the apparatus, a single flexible pipe forthe supply of compressed air could be connected by a suitable manifoldto each of the inlet nozzles 148. Similarly, each of the nozzles 149could be connected by a suitable manifold arrangement to a common outletpipe.

Referring now to FIG. 10, which shows one of the nozzles 147 and theassociated block 143, inlet nozzle 148 and outlet nozzle 149, it can beseen that the block 143 is provided with a boring 150' communicatingwith the inlet nozzle 148 and with a further boring 151 in the block143. One end of the boring 151 is closed by a grub screw 152, and theother end of the boring 151 communicates through an opening 153 in thewall of the outlet nozzle 149 with a boring 154 in a flow constrictionnozzle 155 inserted into the outlet nozzle 149. The flow constrictionnozzle 155 has an axial boring 156 communicating with, and having asmaller crosssection than, the boring 154, and serves to constrict theflow of the compressed air fed in through the inlet nozzle 148 andthereby to accelerate this compressed air.

The powder inlet nozzle 147, which forms a powder inlet through whichthe powder flows to the outlet nozzle 149, is made of plastic materialand has at one end a threaded portion 158 which is in threadedengagement with the block 143. An axial inlet passage extending throughthe nozzle 147 is formed by a first boring 159 extending from the otherend of the inlet nozzle 147 and a second boring 160, which has a largercross section than the first boring 159 and is in axial alignment andcommunication with the first boring 159 and with a frusto-conicallydivergent mouth 161. The mouth 161 communicates through an opening 162in the wall of the outlet nozzle 149 with the interior of the outletnozzle 149 opposite the outlet end of the boring 156 of the flowconstriction nozzle 155.

The powder inlet nozzle 147 has a frusto-conical outer surface 164 whichconverges with the wall of the bore 159 to form a circular knife-edge165 at the outer, inlet end of the boring 159, where the outer surfaceconverges with the bore 159 at the mouth of the inlet nozzle 147.

The block 143 is also provided with a boring 167 extending through theblock 143 for receiving one of the bolts 145 which, together with itsassociated nut 144, serves to clamp the block 143, in a pair of suchblocks, to one of the vertical bracket portions 41, as shown in FIG. 7.

It will be noted that the four powder inlet nozzles 147 extend parallelto one another and to the porous plate 128 and have their inlet endsspaced above the porous plate 128. I

As has been mentioned hereinabove, the vibrator 130 is resilientlymounted within the housing 120. For

this purpose, one wall of the box 126 is formed, as illustrated in FIG.9, with a rectangular opening 170, which is closed by a sheet 171 ofNeoprene (Trade Mark) clamped over the opening-171]! by a rectangularframe 172, which is firmly secured to the box 126 by means of aplurality of screws 173.

The collecting pipe 134 extends through an opening (not shown) in theresilient sheet 171 and is secured thereto by means of a nut 175 (FIG.8), which clamps the resilient sheet 171 against the sleeve 137,suitable washers (not shown) being provided between the nut 175, thesleeve 137 and the resilient sheet 171.

The operation of the above-described apparatus is as follows:

With the powder 114 in the container 110, and the housing 120 resting onthe partition 115 within the powder 114 as shown in FIG. 6, compressedair is supplied to the chamber 118 through the inlet 119, to thevibrator 130 through the flexible pipe 122, and to the powder extractiondevice 121 through the flexible pipes 124.

The compressed air in the chamber 118, which escapes upwardly throughthe-porous partition 115, and also the compressed air from the outlet ofthe vibrator 130, which escapes from the housing 120 through the porousplate 128, forms a fluidized bed of powder around the powder inletnozzles 147, which are caused to vibrate by the motion of the vibrator130, the fluidized bed facilitating flow of the powder through thenozzles 147.

The compressed air entering each of the blocks 143 through therespective compressed air inlets nozzles 148 passes in turn along theborings 150 and 151, through the opening 153, and along the boring 154to the constricted boring 156, from the outlet end of which thecompressed air is discharged as an accelerated jet, which creates apartial vacuum at the mouth 161 of the powder inlet nozzle 147 fordrawing powder through the latter frq the' fluidized bed. The vibrationcaused by the vibrator 130, and the use of the knifeedge 165 at theinlet end of the powder inlet nozzle 147, counteracts the build-up ofpowder at the inlet to the powder nozzle boring 159, which helps toavoid clogging of the latter. The powder, entrained in the acceleratedstream of compressed air jetting from the flow constriction nozzlel55,is carried through the outlet nozzle 149 and along the flexible pipe123.

When it is desired to change-over to a powder of a different colour, thehousing 120 and the powder extraction device 121 are withdrawn as a unitfrom the container 110 merely by pulling the flexible pipes 122, 123 and124, and are then cleaned by means of a suitable suction device toremove any of the powder 114 adhering thereto. 'A burst of compressedair is passed through the powder extraction device 121 to remove any ofthe powder/114 which may be remaining in the flexible pipe 123 and anyapparatus connected thereto. By supplying compressed air through theflexible pipe 122, powder adhering to-the plate 128 can be removed.

In addition, a suitable suction cleaner device is employed to removepowder from the exterior of the housing 120 and the powder extractiondevice 121, and these parts can then be placed in the powder of adifferent colour for conveying that powder.

While the apparatuses described above with reference to the accompanyingdrawings make use of a fluidized bed of powder, it is to'be understoodthat it is not essential to fluidize the powder bed, and that theextractor, devices will operate satisfactorily in nonfluidized powderbeds.

.1 claim:

1. Particulate material spraying apparatus comprising:

a container for particulate material;

an extractor device for extracting particulate material from saidcontainer;

a particulate material discharge device for discharging the particulatematerial;

an outlet duct connecting said extractor device to said dischargedevice;

said extractor device having an inlet nozzle and means defining an inletpassage extending through said nozzle, said nozzle defining a mouth atone end of said inlet passage, said nozzle having an outer surface whichtapers towards said mouth and converges with said inlet passage at saidmouth;

a gas discharge passage extending past the other end of said inletpassage;

means for discharging compressed gas through said gas discharge passagepast said other end into said outlet duct, whereby particulate materialis entrained from said inlet passage and driven through said outlet ductto said discharge device; and

a vibrator for vibrating said nozzle to counteract accumulation of theparticulate material on said nozzle.

2. Particulate material spraying apparatus as claimed in claim 1, andfurther comprising means defining an opening in one side of saidcontainer, said extractor device extending through said opening withsaid nozzle projecting into the interior of said container, and aresilient closure extending between said container and said extractordevice and closing said opening.

3. Particulate material spraying apparatus as claimed in claim 1,wherein said vibrator and said powder extractor device are combined as aunit separate from said container to enable said unit to be readilytransferred from said container to a different container.

4. Particulate material spraying apparatus as claimed in claim 3, andfurther comprising a housing forming part of said unit, said housinghaving an inlet for the entry of compressed gas into said housing and atleast one porous wall portion for escape of the gas from said housing tothe particulate material in said container.

5. Particulate material spraying apparatus as claimed in claim 4,wherein said vibrator has an inlet for flow of compressed gas into saidvibrator to operate said vibrator and an outlet for discharging the gasfrom said vibrator, said vibrator outlet communicating with the interiorof said housing for discharging the gas from said vibrator through theinterior of said housing and through said porous wall portion.

6. Particulate material spraying apparatus as claimed in claim 5,wherein said vibrator is mounted with said housing.

7. Particulate material spraying apparatus as claimed in claim 4,wherein said vibrator is resiliently connected to said housing.

8. Particulate material spraying apparatus as claimed in claim 4,wherein said housing has an opening in one wall thereof, said opening isclosed by resilient material secured to said wall, and said vibrator issupported by said resilient material.

9. Particulate material spraying apparatus as claimed in claim 3,wherein flexible pipes are connected to said housing inlet and saidextractor device outlet for supply of the compressed air and dischargeof the particulate material, said housing and said extraction devicebeing removable from said container by means of said flexible pipes.

10. Particulate material spraying apparatus as claimed in claim 3,comprising a support by which said extraction device is held in apredetermined position in relation to said porous wall portion.

11. Particulate material spraying apparatus as claimed in claim 3,wherein said container has a porous surface for supporting said unit, acompressed gas chamber beneath said porous surface, and a compressed gasinlet opening into said chamber for supplying compressed gas throughsaid chamber and said porous surface to fluidize the powder in saidcontainer.

12. Particulate material spraying apparatus as claimed in claim 4,wherein said container has a porous surface for supporting said housing,a compressed gas chamber beneath said porous surface, and a compressedgas inlet opening into said chamber for supplying compressed gas throughsaid chamber and said porous surface to fluidize the powder in saidcontainer.

13. Particulate material spraying apparatus as claimed in claim 3,wherein said porous wall portion forms a top for said housing.

14. Particulate material conveying apparatus for extracting particulatematerial from a bed of such material, comprising an extractor device,said extractor device having an inlet nozzle, means defining an inletpassage extending through said inlet nozzle, said inlet nozzle defininga mouth at one end of said inlet passage, said nozzle having an outersurface which tapers towards said mouth and converges with said inletpassage at said mouth, and a gas discharge passage extending past theother end of said inlet passage, and a vibrator for vibrating saidnozzle to counteract accumulation of the particulate material on saidnozzle.

15. Particulate material conveying apparatus as claimed in claim 14,wherein said extractor device is adapted for insertion into a containerand formed as a unit separate from the container.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patgnt No.318961998 D t d July 29, 1975 Inventor(s) CHARLES VERTUE It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 41, "In" should be -I-. Column 2, 'line 61, "by" shouldbe --be. Column 5, line 47, "48" should be .l48. Column 6, line 46, "41"should be -l4l.

Signed and Sealed this twenty-first Day of October 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner nfPaIentsand Trademarks

1. Particulate material spraying apparatus comprising: a container forparticulate material; an extractor device for extracting particulatematerial from said container; a particulate material discharge devicefor discharging the particulate material; an outlet duct connecting saidextractor device to said discharge device; said extractor device havingan inlet nozzle and means defining an inlet passage extending throughsaid nozzle, said nozzle defining a mouth at one end of said inletpassage, said nozzle having an outer surface which tapers towards saidmouth and converges with said inlet passage at said mouth; a gasdischarge passage extending past the other end of said inlet passage;means for discharging compressed gas through said gas discharge passagepast said other end into said outlet duct, whereby particulate materialis entrained from said inlet passage and driven through said outlet ductto said discharge device; and a vibrator for vibrating said nozzle tocounteract accumulation of the particulate material on said nozzle. 2.Particulate material spraying apparatus as claimed in claim 1, andfurther comprising means defining an opening in one side of saidcontainer, said extractor device extending through said opening withsaid nozzle projecting into the interior of said container, and aresilient closure extending between said container and said extractordevice and closing said opening.
 3. Particulate material sprayingapparatus as claimed in claim 1, wherein said vibrator and said powderextractor device are combined as a unit separate from said container toenable said unit to be readily transferred from said container to adifferent container.
 4. Particulate material spraying apparatus asclaimed in claim 3, and further comprising a housing forming part ofsaid unit, said housing having an inlet for the entry of compressed gasinto said housing and at least one porous wall portion for escape of thegas from said housing to the particulate material in said container. 5.Particulate material spraying apparatus as claimed in claim 4, whereinsaid vibrator has an inlet for flow of compressed gas into said vibratorto operate said vibrator and an outlet for discharging the gas from saidvibrator, said vibrator outlet communicating with the interior of saidhousing for discharging the gas from said vibrator through the interiorof said housing and through said porous wall portion.
 6. Particulatematerial spraying apparatus as claimed in claim 5, wherein said vibratoris mounted with said housing.
 7. Particulate material spraying apparatusas claimed in claim 4, wherein said vibrator is resiliently connected tosaid housing.
 8. Particulate material spraying apparatus as claimed inclaim 4, wherein said housing has an opening in one wall thereof, saidopening is closed by resilient material secured to said wall, and saidvibrator is supported by said resilient material.
 9. Particulatematerial spraying apparatus as claimed in claim 3, wherein flexiblepipes are connected to said housing inlet and said extractor deviceoutlet for supply of the compressed air and discharge of the particulatematerial, said housing and said extraction device being removable fromsaid container by means of said flexible pipes.
 10. Particulate materialspraying apparatus as claimed in claim 3, comprising a support by whichsaid extraction device is held in a predetermined position in relatIonto said porous wall portion.
 11. Particulate material spraying apparatusas claimed in claim 3, wherein said container has a porous surface forsupporting said unit, a compressed gas chamber beneath said poroussurface, and a compressed gas inlet opening into said chamber forsupplying compressed gas through said chamber and said porous surface tofluidize the powder in said container.
 12. Particulate material sprayingapparatus as claimed in claim 4, wherein said container has a poroussurface for supporting said housing, a compressed gas chamber beneathsaid porous surface, and a compressed gas inlet opening into saidchamber for supplying compressed gas through said chamber and saidporous surface to fluidize the powder in said container.
 13. Particulatematerial spraying apparatus as claimed in claim 3, wherein said porouswall portion forms a top for said housing.
 14. Particulate materialconveying apparatus for extracting particulate material from a bed ofsuch material, comprising an extractor device, said extractor devicehaving an inlet nozzle, means defining an inlet passage extendingthrough said inlet nozzle, said inlet nozzle defining a mouth at one endof said inlet passage, said nozzle having an outer surface which taperstowards said mouth and converges with said inlet passage at said mouth,and a gas discharge passage extending past the other end of said inletpassage, and a vibrator for vibrating said nozzle to counteractaccumulation of the particulate material on said nozzle.
 15. Particulatematerial conveying apparatus as claimed in claim 14, wherein saidextractor device is adapted for insertion into a container and formed asa unit separate from the container.